1. Field of the Invention
The invention relates to an encoding module, and more particularly to an encoding module that is easily assembled.
2. Description of the Related Art
A cursor input device, such as a mouse, can be used to control cursor movement and function selection. A conventional mouse used with a personal computer is usually a two-dimensional one for controlling the cursor movement on an X-Y plane on the monitor screen.
However, such a two-dimensional mouse can no longer meet users needs in view of the increased requirement for convenience in operational operating system interfaces. A three-dimensional mouse, which can be used to define a certain system control function, has been disclosed in U.S. Pat. Nos. 5,530,455 and 5,808,568. However, the devices disclo in U.S. Pat. Nos. 5,530,455 and 5,80.8,568 require many more components, than required for a two-dimensional mouse thereby resulting in inconvenience during assembly.
Therefore, the object of the present invention is to provide an encoding module that can be easily assembled.
According to the present invention, an encoding module is adapted for a cursor input device and includes an optical encoder roller, a roller supporting frame, a base member, installing means, biasing means, a switch, and rotation control means.
The optical encoder roller has first and second lateral surfaces, a plurality of angularly disposed apertures that extend through the first and second lateral surfaces, and an axle extending axially through the roller, and has opposite end portions that project respectively from the first and second lateral surfaces.
The roller supporting frame has front and rear parts and opposite lateral parts that interconnect the front and rear parts to form the roller supporting frame with a roller opening. Each of the lateral parts is formed with an upwardly extending axle support that has a respective one of the end portions of the axle mounted thereon such that a lower portion of the roller extends through the roller supporting frame at the roller opening and such that the roller is rotatable relative to the roller supporting frame about a horizontal axis. The roller supporting frame further has a switch actuating block that extends from one of the lateral parts outwardly of the roller opening.
The installing means installs the roller supporting frame on the base member such that the roller supporting frame is movable vertically toward and away from the base member.
The biasing means is disposed between the base member and the roller supporting frame for biasing the roller supporting frame upwardly and away from the base member.
The switch is mounted on the base member, and is disposed below the switch actuating block such that downward movement of the roller supporting frame relative to the base member will enable the switch actuating block to engage the switch.
The rotation control means, which is provided on the roller and the roller supporting frame, enables intermittent releasable engagement between the roller and the roller supporting frame so as to permit rotation of the roller relative to the roller supporting frame in seeps.